The present invention relates to electrical contact probes, and more particularly to a high density probe suitable for contacting the high density leads of integrated circuit devices, the high density probe registering locally with the device rather than globally with the board upon which the device is mounted.
As integrated circuit technology progresses the circuitry contained in an integrated circuit package becomes more and more compact, resulting in smaller packages and higher lead densities. To test these integrated circuits packages when installed on a board in a completed system several techniques have been used. In the factory a large probe machine that globally registers with the board may be used to precisely probe any desired lead of any integrated circuit package regardless of any local misregistration of the package since the leads themselves are precisely registered. However for field use with logic analyzers or multi-channel oscilloscopes it is not feasible to have such large probe machines. Therefore probes have been developed that fit into the integrated circuit sockets on the board, with the integrated circuit then being mounted on the probe. This is feasible so long as the integrated circuit package is not fixed to the board. Alternatively when the integrated circuit package is fixed to the board, such as is the case for a surface mount package, various types of grabber probes have been developed to grab individual leads of the integrated circuit package. As the density of the leads increases the danger of shorting adjacent leads with the grabber probes also increases. For lead densities of 0.025" and less between lead centers it becomes extremely difficult to successfully test, or probe, the integrated circuit package.
Therefore what is desired is a high density probe that can be precisely registered locally with an integrated circuit package and that precisely aligns the probe pins with the leads of the integrated circuit package.